$(document).ready(function() {
    $('.decorate-with-timepicker').timepicker();
    $('select.timepicker').change();
});

var availableTimeZones = {};
availableTimeZones["300"] = "America/New_York";
availableTimeZones["0"] = "Europe/London";
availableTimeZones["-180"] = "Europe/Moscow";
availableTimeZones["-480"] = "Asia/Singapore";

function preselectTimeZone(sel) {
    var myDate = new Date();
    var tz = availableTimeZones["" + myDate.getTimezoneOffset() + ""];
    if (tz != null) {
        sel.val(tz);
    }
}